P1.020: MIS-C in the Post-Pandemic Era: A Patient with Obesity, Shock, Lactic Acidosis and Severe Insulin Resistance

Introduction: Multisystem inflammatory syndrome in children (MIS-C) has become infrequent post pandemic. Children with severe obesity and diabetes mellitus (DM) are increasingly common in a PICU. We present a case of presumptive MIS-C complicated by DM with severe insulin resistance that posed multiple challenges to ICU management.

Case Description: A 14-year-old obese male with Prader Willi Syndrome and Type II DM was intubated for hypoxemic and hypercarbic respiratory failure after presenting with dyspnea, weakness and fatigue. Home medications were metformin, pioglitazone and weekly semaglutide, a GLP-1 receptor agonist. Chest radiograph showed right lower lobe consolidation and cardiomegaly. Hypoxemia (PaO2/FiO2 = 140), elevated lactate (4.9), transaminitis (AST 2029, ALT 1630), and hyperglycemia were present. Norepinephrine, piperacillin/tazobactam and vancomycin were started. He was tachycardic with biphasic wheezing, crackles, hepatomegaly and edematous feet. Weight was 123 kg (BMI > 99%, Z = 4.6). BNP (119) and troponin (0.31) were elevated. ST segment changes concerning for myocarditis were present on EKG. Echocardiogram demonstrated moderately depressed LV function (LVEF 51.2%) and normal coronary arteries. Milrinone was added. He remained febrile. COVID spike antibodies, ferritin, C-Reactive protein and procalcitonin were elevated to 7393, >1676, 28.7 and 1.25, respectively. IVIG and methylprednisolone were initiated for possible MIS-C. With a rising serum lactate, metformin associated lactic acidosis (MALA) was considered and metabolic resuscitation with thiamine and dextrose was begun. Hyperglycemia persisted despite increasing the IV insulin to an unusually high rate of 0.49 units/kg/hr of actual body weight. Insulin glargine and a daily GLP-1 receptor agonist, liraglutide, were started and the IV insulin requirement gradually decreased. After 2 months, he was extubated to BiPAP and eventually transferred to a rehabilitation facility.

Discussion: Despite its decreased prevalence, MIS-C remains a concern. Metformin, though safe and efficacious for Type 2 DM, can result in Type B lactic acidosis. Metabolic resuscitation with thiamine showed efficacy in this patient. Using actual body weight rather than ideal weight resulted in improved glucose control, though large amounts of insulin were required. Significant inflammation can lead to increased insulin resistance. Addition of a GLP-1 receptor agonist can help overcome this by stimulating insulin secretion, suppressing hepatic glucagon release and decreasing the amount of exogenous insulin required.

Conclusion: MIS-C has become rare post pandemic as well as in patients vaccinated for COVID. This patient met criteria for MIS-C. No other infectious etiology was found. Obesity, insulin resistance, complex diabetic management regimens including GLP-1 receptor agonists are becoming common in pediatrics. The occurrence of MALA and a requirement for metabolic resuscitation with thiamine may be missed. This patient presented many challenges but with a rich educational benefit.